Telephone-receiver.



Patented' Feb. Il, |902.

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(Application led Apr. 29, 1901.)

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UNITED STATES,

PATENT OFFICE.

JAMES G. NOLEN, OF CHICAGO, ILLINOIS.

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SPECIFICATION forming' part of Letters Patent No. 692,897, dated February 1 1, 1902.

Application tiled April 29, 1901. Serial No. 57,858. (No model) To all whom it may concern:

Be it known that I, JAMES G. NOLEN, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Telephone-Receivers; and I hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, which form part of this specification.

My invention relates to improvements in telephone-receivers.

One object of my invention is to provide a telephone-receiver in which the magnetic and electrical system may be bodily removed from the protecting-case without disturbing any electrical connections.

Another object of my invention is to provide a means whereby the magnetic system may be adjusted with reference. to the diaphragm so that the expansion and contraction of the case will not disturb the adjustment.

Another object of my invention is to provide a number of perforations through the cap-piece which covers the diaphragm, so that the sound may issue therefrom through a number of apertures instead of a central aper-Y ture, as is common with instruments of this character.

In the drawings, Figure l is a vertical section of my telephone-receiver. Fig. 2 is the inner pole of the magnet carrying the indue, tion-coil and a means by which the said magnet is connected to the surrounding cylindrical magnet, which is a part of the magnetic system. Fig. 3 is a top view of the cap or ear piece of the telephone-case'. Fig. 4 is a section through line 4 4 of Fig. l.

In all of the Views the same letters of reference indicate similar parts.

A is the insulating containing-case. a is an annular bead or enlargement around the lower end thereof.

o.' is the threaded upper portion, to which the interiorly-threaded cap is attached.

cisa thread cut into the upper interior portion of the telephone-case A for the purpose of attaching the magnetic system thereto.'

a3 is a hard-rubber or other-.insulating disk which forms a cap to cover the opening in the lower end of the telephone-case.

a4 and a5 are screws that are adapted to pass through the cap and. to secure it to the magnetic system.

Bis a concave cap that is adapted to be screwed over the upper end of the telephonecase for holding the diaphragm in position thereon. Z2 represents a number of perforations through the said cap, which communicate with the space therein over the diaphragm.

C is a magnetized steel tube which forms a part of the magnetic system. c is the rounded polar end of the same.

C' is a magnetized steel rod which forms a part of the magnetic system. c' is the polar end of the said rod, surrounded by the electric coil c2. c3 c3 are the terminal binding-posts, which are connected with the said coil and which are attached to the insulating cappiece a3.

c4 is a ring which is fixed tightly around the lower end of the cylindrical magnet C.

c5 is an iron cap or yoke for joining the two magnets, in thercenter of which the magnetized rod VC is secured in the perforation c6.

c7 is an eXteriorly-threaded thimble which is adapted to tit tightly over the upper end of the magnetic cylinder C and which is adapted to be screwed into the threaded interior of the telephone-case A at a2. A check-nut o8, having Spanner-holes in its upper surface, is adapted to be screwed over the exteriorthreaded thimble c7 for the purpose of securing the magnetic system permanently in po sitionwith reference to the diaphragm when it is tightened on the upper portion of the case A after suitable adjustment has been made. The magnetic circuit between the interior magnetized rod and the surrounding magnetized cylinder is completed through the shouldered iron washer c5, which is held in contact with the lower end of the magnetized tube C by means of the screws a4 and d5, which pass through the cap a3 and the cap or washer c5 and into the ring c4. By this construction the cap c5 is held in contact with the exterior ring, and the insulating-cap a3 is held in position IOO thereon, whereby the magnetic and electrical portion of my device becomes as a single unit, which may be bodily removed from the case Without disturbing the magnetic orl electrical connections or conditions.

I have found fromexperiment that rounding the upper polar surface of the magnetic cylinder, as shown at c, is ot great importance and contributes materially tol the effective operation of the instrument.

By perforating the cap B with small holes h instead of using one large hole in the center thereof, as is the usual custom, it becomes a matter of indifference as to the exact position of the telephone-cap with reference to the ear of the operator when using my receiver, as it is hardly possible to hold the cap of the receiver to the ear Without the interior of the car covering one or more perforations in the said cap. Another advantage of perforating the cap of the receiver is to prevent foreign substances from entering the cap or the space between the upper portion of the diaphragm and the said cap. It also prevents meddlesome persons or users of the instrument from disturbing the adjustment by pressing on the diaphragm through the central larger aperture, the perforations in my instrument being so small as to render it impossible for them to materially injure the diaphragm from .the exterior of the instrument. f

It is sometimes an advantage to be able to remove the entire electrical portion of the instrument from the case Without disturbing the connections or their relations and to be able to insert another duplicate or interchangeable portion in lieu of the injured or disarranged one that has been removed. The magnet may be secured in the case after it has been properly adjusted for position by tightening the screws a4 and a5 to increase the friction upon the threads of the parts a2 and c7 and to retain the case and magnet in a fixed relation, in which event the check-nut cs may be dispensed with.

It is evident that'the cap having the multiplicity of perforationsinstead of one cent-ral perforation, as is usual with telephone receivers and transmitters, may be used with a telephone-transmitter with benecial results Without departing from the gist of my invention.

I-Iaving described my invention, what I claim as new and useful, and desire to secure by Letters Patent of the United States, is-

In a telephone-receiver the combination ot' a diaphragm, a cylindrical magnet having its polar end rounded, a magnetized rod Within said cylindrical magnet, a coil near the polar ends of said magnet, a case covering said magnets, screw-threads in said case,lscrew threads ou said magnet, and a checkfnut on said magnet for holding said magnet and said case in a xed relation, substantially as set forth.

In testimony that I claim the foregoing as my own I affix my signature in presence of two witnesses.

JAMES Gr. NOLEN.

C. INEZ WILcoX, M. F. ALLEN. 

